1. Field of the Invention
Aspects of the present invention relate to an image-forming apparatus, and more particularly, to an image-forming apparatus having a device to attach/detach a transfer roller from a main body of the image-forming apparatus.
2. Description of the Related Art
Generally, an image-forming apparatus prints a desired image on a sheet of print medium by: forming an electrostatic latent image on a photosensitive medium using an exposing unit, such as a laser scanning unit; developing the electrostatic latent image into a toner image using toner; and transferring and fixing the toner image onto the sheet of print medium by applying heat and pressure thereto.
Thus, the image-forming apparatus comprises a transfer roller that rotates in contact with the photosensitive medium to transcribe the toner image onto the sheet of print medium. The transfer roller is detachably mounted to the main body and can be easily replaced with a new one.
FIG. 1 is a perspective view illustrating a conventional transfer roller assembled to a main body, and FIG. 2 is a perspective view illustrating an operation for assembling the transfer roller of FIG. 1 to a main body.
Referring to FIGS. 1 and 2, a transfer roller 10 is supported by a circular supporting unit 31 and a hemispherical supporting unit 32 disposed on a main body frame 30. Each of the ends 11a and 11b of a transfer roller axis 11 of the transfer roller 10 is supported to rotate by the circular supporting unit 31 and the hemispherical supporting unit 32.
The end 11a of the transfer roller axis 11 is inserted into a circular bushing 21, and the circular bushing 21 is supported by the circular supporting unit 31. The other end 11b of the transfer roller axis 11 is rotatably supported by a fixing unit 40 which is disposed on the main body frame 30 and inserted into the hemispherical supporting unit 32.
As depicted in FIG. 2, the fixing unit 40 is designed to deform elastically when the other end 11b of the transfer roller axis 11 is pushed downward from an upper side. When the other end 11b of the transfer roller axis 11 is inserted into the hemispherical supporting unit 32, the fixing unit 40 returns to an original position and restricts the other end 11b of the transfer roller axis 11 from moving upward.
To mount the transfer roller 10 to the main body frame 30, the fixing unit 40 is elastically deformed by pressing the other end 11b of the transfer roller axis 11 downward from an upper side. To separate the transfer roller 10 from the main body frame 30, the other end 11b of the transfer roller axis 11 is lifted after releasing it from the fixing unit 40 by elastically pressing the fixing unit 40 using a tool or by hand.
Therefore, when the transfer roller 10 is mounted to the main body frame 30, an assembling space must be secured, and when the transfer roller 10 is separated from the main body frame 30 to replace it by a new one, the separation operation is difficult due to a small area of the assembling space.